


Mana Concoction

by thaaats piss buddy (Resident_of_Fiction)



Category: Fate/Grand Order
Genre: Gen, Omorashi, Wetting
Language: English
Status: Completed
Published: 2020-10-06
Updated: 2020-10-06
Packaged: 2021-03-08 09:14:59
Rating: Mature
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,021
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/26849506
Author URL: https://archiveofourown.org/users/Resident_of_Fiction/pseuds/thaaats%20piss%20buddy
Summary: Apparently some potions can have diuretic side effects.
Comments: 1
Kudos: 12





	Mana Concoction

**Author's Note:**

  * For [FatePissOrder (poludeuces)](https://archiveofourown.org/users/poludeuces/gifts).



After all that time stuck in the Shadow Border, being able to freely stretch their legs in the Wandering Sea was a welcome relief to the remaining members of Chaldea. And once they were able to re-summon the other Servants, it almost seemed as if things hadn’t changed. 

Though of course, some things had changed, Holmes thought with a slight wince as a flash of pain shot across his right side. It would be awhile until he fully recovered from the injury he received in the Norse Lostbelt. He couldn’t fight yet, and his body was weaker, but for now he was able to get by with just a regular check-up from Da Vinci. One of which was occurring at the current moment.

“You okay?” the small genius asked, glancing back up at him from her screen.

“Yes, I’m fine,” he said, redoing the buttons on his shirt. “It’s no cause for concern.”

“Hm hm hm…” Da Vinci hummed, reading his mana levels. “Everything seems good here. The healing is slow, but it seems to be on schedule.” 

He put his coat back on as well. “Thank you,” he said. “I must be going now. I have some matters to attend to in my workshop.”

"Yeah sure, I won't keep you. But first," Da Vinci said, pulling a bottle of strange blue liquid from a cabinet and pouring some into a plastic cup, “drink this."

He eyed it. “A mana concoction of some sort?” 

“This _should_ help your recovery a bit, but well…” She shrugged.

“You’re not quite sure of the side effects?”

“I haven’t needed to use it before now,” she said. “But I figured, well, you’re a man of science right? It’s not going to kill you, that’s for sure.” 

He took the cup from her. “This is certainly not the first untested substance I’ve put into my body,” said Holmes with a smirk. With one swirl of the liquid, he lifted it to his lips and swallowed. The flavor was mild, barely noticeable in fact. 

Da Vinci watched him for any sort of reaction, then looked back at his readings. She smiled. “Alright, that should do it. Let’s do this again in hm… two days?”

“Yes, thank you again,” Holmes said and stood up. 

As he was leaving Da Vinci said, “Let me know if the mana potion causes any weird symptoms.” 

With a nod to her he left and was on his way to his new workshop. He felt a bit of a need to pee, and briefly considered the option of stopping to take care of that first, but ultimately decided to wait. The urge was barely noticeable, and fixing the equipment he was working on shouldn’t take very long. 

Holmes arrived there with a slight sigh as the door shut behind him. This new room which had been prepared for him wasn’t quite identical to his old one. The general shape of the room was similar, though it was a bit smaller, to his mild disappointment. All his instruments and tools had been lost with the original Chaldea, but the Nemo Engineers had been considerate enough to lend him some new ones. A variety of different projects and plans were scattered about, on the floor and shelves. To an outsider, it was not nearly as organized as Da Vinci’s workshop, but one would never have an opportunity to think such a thing given he didn’t let anyone in here. 

On the main desk lay a half-disassembled magical instrument, a device made of several bending and protruding metal rods and glowing green core. His task wasn’t very complicated. A simple piece of machinery that needed to be fiddled with. He sat in his desk chair, rolled up his sleeves, picked up a screwdriver, and got to work. 

He didn’t pay too much attention to the passage of time—he never did with these sorts of things—but even he knew it hadn’t been that long when his bladder once again made itself known. Again choosing to ignore it, he grabbed another piece of the machine and began tinkering.

A turn of his screwdriver, an adjustment of a metal plate, a shift in his seat as he felt another wave of desperation. This was manageable. He twisted some wires, grabbed a bulb he’d scavenged from a different device, and adjusted his hips again. 

Setting aside his tools, he tried picking up the object by hand. The magical core gave his fingers a shock, nothing too bad, not enough to make him pause for more than a moment, but the surprise still had his thighs pressing and rubbing together. His urgency was quickly growing. Strange. Still, it wasn’t anything dangerous yet.

Holmes kept at it, though soon he needed to cross his legs. By now his concentration was slipping just a bit. He squinted at the device. It should be working by now. He ground his teeth and leaned forward in his chair. 

“Confounded thing…” he said to himself.

He picked up a wrench and tried to get the metal and magical bits to align correctly. By now he was practically squirming. With another sigh, of annoyance this time, he stood up to grab something from the other side of the room. And he leaked.

With a sharp gasp he doubled over and shot a hand down to grab his crotch. How the hell had it managed to get this bad in a matter of minutes? He thought he’d calculated how long he could wait. He’d had a mild need only a short while ago and now it felt as if he was on the verge of wetting himself.

No, the answer was obvious, he thought as he stumbled towards the door and opened it. Even an idiot with no deductive skills could figure out this mystery. He was sure Da Vinci would get a good laugh out of this.

Holmes went back down the same hallway he’d just come through. His stride was quick, not a run, but faster and with more energy than he had exerted since his injury. His hand was locked tightly in between his legs, hoping to stop himself from leaking again.

There was a single stall toilet not too far. A mere two minutes or so walk. He squirmed the whole way, thankful his workshop was far from the more occupied Servants’ quarters. But finally, there it was in sight. He’d made it. With his free hand he grabbed the door handle and pulled. 

Locked.

Right, of course. He tried to slow his rapidly beating heart. This bathroom was meant for one person. He just needed to wait another minute. In fact, to both his relief and shuddering, he could hear the sink running on the other side. Whoever was in there now had just finished.

Still, it couldn’t hurt to speed them along. He knocked.

“Just a moment,” came the voice.

With a sickening dawning horror, Holmes watched his only chance of not pissing himself slip away into the void. He removed his hand from his crotch and tried to keep perfectly still, but he couldn’t prevent his thighs from smashing together.

The door opened. 

“Alright it’s— _Oh_ … what do we have here?” the person said, with a tone and a smile that could only be described as simply: evil. 

Holmes grimaced as more piss leaked. “Hello, Professor,” he said through gritted teeth.

Moriarty rested his elbow against the doorframe and leaned his cheek against his fist. “What a pleasure to see you here, Holmes,” he said with a smug smirk. “I don’t believe we’ve had the time to chat since I was resummoned.” 

Giving a wry smile in return, Holmes said, “We shall have to have a chat over tea sometime then.” He racked his brain for what he could say. But no… with the state he was in, Moriarty knew exactly what was going on. Holmes’ toes curled in his shoes as he begged his hands not to grab his crotch again against his will. 

“What’s the matter, Holmes?” the old man said. “You don’t look very well. You look as if you just fell over Reichenbach a second time. With how mighty those falls were… I’m sure you must have been absolutely _drenched_.”

There it was. He bit the inside of his lip. Another spurt.

“I heard you used me to break your fall—and how horrible of you for that, by the way—yet it’s still a wonder how you survived all that rushing water.”

“I’m an excellent swimmer,” he answered with a smirk that certainly wasn’t its usual self. He could just land a baritsu kick on Moriarty’s face and knock him out… usually anyway. If he tried to raise his leg to do so now it was obvious what would happen. All of his deductive reasoning knew there was no hope. However… 

A sound most unlike him escaped from his lips as his underwear got even wetter. Surely it must be leaking through to his trousers at this point… And glancing at Moriarty’s pleased grin, yes, that’s exactly what happened.

In a last ditch effort, Holmes tried shoving Moriarty aside with his shoulder to get past him, rushing in with all his strength. 

But Moriarty put up no force to stop him, turning his body to the side, and Holmes went flying past him, nearly tripping before catching himself with a steady bit of footwork. However, doing so took all the remaining amount of willpower he had in him.

“Damn it...!” With a cry that acted as a resignation, piss burst forth from him, running down his thighs, completely soaking his trousers, and spreading on the tiled floor. He couldn’t even attempt to stop it at this point. His body was too weak and tired. 

“Ah… ah…” A blissful high came over him as the relief was overpowering, and he briefly considered the possibilities of combining this feeling with one of his drugs of choice. He hadn’t even realized he’d been this tense. Not just from his desperate need to relieve himself, but from all of it. The destruction of Chaldea, the Lostbelts, his injury… For the first time in ages he felt as if he could just let it all go, to flow out of him with all the liquid he’d been keeping inside. 

A laugh came from behind him, bringing him back from his relaxed dream. “Would you look at that! The great detective, pissing himself right in front of the toilet. What a delightful gift you’ve given to me, Holmes.”

Though he knew for a fact his face had turned bright red, his relief from before turning to shame and embarrassment, his head was also a lot clearer now. “An unfortunate occurrence,” he said. “Though I might point out that your sincere enjoyment of watching an injured man lose control of himself is rather petty and childish, but I would expect nothing less of you, Professor.”

Moriarty gave an exaggerated shrug. “I’m not one to simply pass up opportunities as they come. Well, thank you again, but I must be off. Babbage and I were in the midst of playing a riveting game of Old Maid with Fran.” 

With that and an airy wave, he left, leaving Holmes standing in a puddle of his own piss. 

Holmes gave another sigh, glancing down at himself and the mess he’d made. Da Vinci certainly was going to get a laugh out of this.

* * *

_The next day._

The cafeteria was bustling as Servants went about their breakfast rituals. Holmes was sitting in his usual spot, drinking tea and helping himself to some toast, when he heard the voice of a girl talking to someone a short distance away.

“Papa. Pants are… wet?”

“Wha—?”

Holmes glanced up to see a wet patch slowly spreading across Moriarty’s front and running down his legs. He took another sip of his tea. “Your age appears to be catching up with you, Professor,” he said.

Moriarty whipped his head towards him, his mustache crinkling in fury. “You! You drugged me!”

“What a horrible accusation. Do you have any proof?”

“ _ **Holmes!**_ ”


End file.
